Abstract
The water distribution castellum at the terminal end of the Pont du Gard aqueduct serving the Roman city of Nemausus in southern France is analyzed for its water engineering design and operation. By the use of modern hydraulic engineering analysis methods applied to analyze the castellum, new aspects of Roman water engineering technology are discovered not previously reported in the archaeological literature. Analysis of the castellum’s 10 basin wall flow distribution pipelines reveals that when a Roman version of modern critical flow theory is utilized in their design, the 10 pipelines optimally transfer water to city precincts at the maximum flow rate possible with a total flow rate closely approximating the input flow rate from the aqueduct. The castellum’s three drainage floor ports serve as additional fine-tuning to precisely match the input aqueduct flow rate to the optimized 10 pipeline output flow rate. The castellum’s many hydraulic engineering features provide a combination of advanced water engineering technology to optimize the performance of the water distribution system while at the same time enhancing the castellum’s aesthetic water display features typical of Roman values. While extensive descriptive archaeological literature exists on Roman achievements related to their water systems both in Rome and its provinces, what is missing is the preliminary engineering knowledge base that underlies many of their water system’s designs. The present paper is designed to provide this missing link by utilizing modern hydraulic engineering methodologies to uncover the basis of Roman civil engineering practice—albeit in Roman formats yet to be discovered.
Highlights
The Pont du Gard aqueduct, built during the reign of Claudius (40–60 AD), involves many unique hydraulic engineering components and strategies [1,2,3,4] that collectively worked to deliver water to the Roman city of Nemausus [2,3,5]— the city of Nîmes in southern France
Given that calices work only under full-flow conditions, their use by Roman engineers in the castellum pipeline entry ports may have appeared useful for precise flow rate delivery to destination sites given that full flow at basin wall pipeline entrances could be maintained by means of a horizontal pipeline elements before pipeline declination slope continuance converted full to partial flow in pipeline extensions to the lower city
Roman hydraulic knowledge at work in many ways— in the use of a shallow, wide-diameter basin with the retaining basin wall slightly higher than the top of the pipeline entrance ports. This design initiates basin input flow from the aqueduct water entrance port into pipeline entrances at critical, partial flow conditions; its continuance as critical or nearcritical flow is guaranteed by appropriately sloped pipelines to important city destinations
Summary
The Pont du Gard aqueduct, built during the reign of Claudius (40–60 AD), involves many unique hydraulic engineering components and strategies [1,2,3,4] (pp. 181–188 [1]) that collectively worked to deliver water to the Roman city of Nemausus [2,3,5]— the city of Nîmes in southern France. The Pont du Gard aqueduct/bridge spanning the Gardon River (Figure 2A–C) is located ~25 km from the spring source; a further 25 km extension of the aqueduct channel constructed partway through a tunnel delivered water to the basin distribution center (castellum) located ~17 m above the city of Nemausus. The castellum was designed for use at the maximum 40,000 m3 /day flow rate that the Uzés spring source could supply on a steady basis—this being necessary to provide sufficient water for the large city population. A ( lost) movable sluice gate (Figures 3–5) regulated the basin water height into the 10 basin wall pipelines and played a vital design role in the operation of the castellum. Water containment in channels during rainfall events was anticipated by the channel wall height design, the use of the three castellum basin floor ports to dispense excess water arriving to the castellum over the design flow rate kept the basin from overflowing maintaining its aesthetics even during rainfall events
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
